Cereal Chem 42:97 - 106.  |  VIEW ARTICLE

Proteolytic Action of Wheat Flour on Nonfat Dry Milk Proteins.

J. E. Bernardin, D. K. Mecham, and J. W. Pence. Copyright 1965 by the American Association of Cereal Chemists, Inc. 

In pH 3.1 aluminum lactate or 0.01N acetic acid, flour protease rapidly attacked the alpha(s)-casein of nonfat dry milk. Starch-gel electrophoresis in aluminum lactate buffer and 7.5M urea readily separated three fragments that differed markedly in mobility. Starch-gel electrophoresis of the acidic digests in tris-citrate buffer, pH 8.6, confirmed the alteration of alpha(s)-casein, although only two fragments were resolved. Upon prolonged digestion, the faster-moving components disappeared. Other milk proteins (beta- and kappa-caseins, beta-lactoglobulin, alpha-lactalbumin) were not observably attacked under conditions leading to alteration of all alpha(s)-casein. The protease attacking alpha(s)-casein was present in all flours examined (five HRS, five HRW). The pH 3.1 aluminum lactate buffer gave good resolution of milk-protein components, and of mixtures of milk- and flour-protein components.